Seafood Casserole

Seafood casserole is the perfect meal for seafood lovers! It's the perfect comfort food for any occasion. The mixed seafood combined with the homemade alfredo sauce is an absolute dish made in heaven. Serve this casserole at your next party or gathering and watch it disappear! Everyone will love its creamy and cheesy goodness and taste of coastal cuisine right in your own home.

What Do You Serve With Seafood Casserole?

Seafood casserole is delicious on its own, but if you're looking for something to serve alongside it, this mashed potato casserole or even baked potatoes are excellent choices. Rice pilaf or quinoa are also great ideas for a starch side to go with the casserole.

It pairs perfectly with asparagus casserole or spinach casserole, but you might want to add a side of your favorite steamed vegetables or pasta to this. And, of course, it also pairs well with a glass of white wine.

fork of seafood casserole held above ramekin of casserole

Ingredients

1 ½ cups whole milk (350ml)
4 tablespoons butter (57g)
5 tablespoons all-purpose flour (40g)
¼ cup grated Parmesan cheese (22.5g)
⅛ teaspoon nutmeg (.25g)
2 garlic cloves
1 ½ pounds seafood mix (750g)
1 cup shredded cheddar cheese (118g)

Note: I used a frozen bag of mixed seafood for this recipe. If you prefer, you can choose the exact items in a mixture of your preference. Just make sure they are thawed and patted dry before adding them to the sauce to cook.

ingredients in white ramekins on marble table

Kitchen Tools You Need

cheese topped seafood casserole in oval ramekin on wire rack

How to Make a Seafood Casserole

Start by thawing your seafood and then patting it dry. Set this aside for later. Then, preheat the oven to 350°F/180°C and spray your baking dish(es) with non-stick spray. I used two ramekins, but you can fit this into a 9"x9" or 10" oval dish if preferred.

In a large saucepan or skillet, melt the butter over medium heat. Once melted, whisk in the flour to create a roux.

flour added to melted butter in skillet on black hot plate

Once the flour and butter are combined, add the minced garlic and cook for 1 additional minute, just until fragrant. You don't want to brown the flour, just heat everything through.

Then, whisk in the milk, nutmeg, and grated Parmesan cheese. You want to whisk this until no lumps remain. Then you will simmer this, stirring regularly, for about 10-minutes or until it has formed a thickened "alfredo" sauce.

spices being added to cream sauce in skillet

Now you will add the thawed and dried seafood mixture. The mixture used here included shrimp, clams, oysters, mussels, scallops, and octopus. You can use any variety of fresh or frozen seafood that you prefer.

Stir the seafood and sauce together well then cook for an additional 5-minutes.

mixed seafood being poured into cream sauce in skillet

Once it is cooked and heated through, pour the mixture into the prepared pan or ramekins. Spread the shredded cheese over the top of the casserole(s).

hand sprinkling cheese on top of ramekins of seafood casserole

Bake for 15 minutes or until the casserole is heated through and the cheese has melted. For added color, broil for 2 minutes.

fork holding shrimp above ramekin of seafood casserole

Frequently Asked Questions

What is Seafood Casserole

Seafood casserole is a mixture of seafood that is all baked together in a homemade white sauce similar to alfredo sauce. It's all topped with cheddar cheese and baked to perfection. While I have used a frozen seafood blend, you can customize this recipe to whatever your family will enjoy most.

What Seafood Goes in Seafood Casserole?

This seafood casserole has crab, clam, mussels, octopus, and shrimp. You can use any type of seafood you like in this casserole. If you don't like one of the types of seafood listed, feel free to leave it out or swap it for something else. Some other great options include scallops, lobster, or salmon.
The best part of any casserole is that it is easy to make your own.

How Long is Seafood Casserole Good For?

This casserole can be stored in the fridge for up to four days. If you want to make it ahead of time, it can also be frozen for up to two months. When you're ready to eat it, let it thaw in the fridge overnight and then bake it according to the recipe instructions.

white oval ramekin of seafood casserole on wire cooling rack

How to Store Leftovers

If you are using fresh seafood instead of frozen, it is best to cook it within 2 days. Once cooked, it can last up to 4 days in the refrigerator but is much better in the first 48 hours.

To store leftovers, I recommend keeping them in an airtight container in the refrigerator. Once ready to serve, you can pop it into the oven or microwave to reheat. However, if using the microwave, reheat in 30-second increments to prevent the seafood from getting rubbery.

If you are freezing this for later, let the dish cool completely before transferring it to freezer storage containers. Date and label them with cooking directions, and freezer for up to 2 months. The seafood can be frozen longer, but the sauce begins breaking down and isn't as good once reheated after that time period.

two oval white ramekins on wire rack with checked napkin in background

More Easy Casserole Recipes

This seafood casserole is a great choice if you want to serve something that is fast and easy to prepare but feels a bit upscale. If you want more cheesy and creamy recipes on your menu, check out a few more of my favorites below. Make sure you bookmark them, print out the recipes, or pin them to Pinterest to make soon.

Yield: 4

Seafood Casserole

A delicious homemade cream sauce, mixed seafood, and cheese combine to create a perfect entree for your meal plan!

Prep Time 15 minutes

Cook Time 15 minutes

Total Time 30 minutes

Ingredients

1 ½ cups whole milk (350ml)
4 tablespoons butter (57g)
5 tablespoons all-purpose flour (40g)
¼ cup grated Parmesan cheese (22.5g)
⅛ teaspoon nutmeg (.25g)
2 garlic cloves, minced
1 ½ pounds seafood mix (750g) - thawed and patted dry
1 cup shredded cheddar cheese (118g)

Instructions

Preheat the oven to 350°F/180°C and spray two ramekins or a 9"x9" baking dish with non-stick spray and set them aside.
In a large skillet, melt the butter over medium heat. Once the butter is melted, whisk in the flour until smooth.
Add the minced garlic, stir, and cook for an additional 1 minute.
Now, whisk in the milk, nutmeg, and grated Parmesan cheese. Whisk this together with the flour and garlic until no lumps remain, then cook for around 10-minutes, stirring regularly, until the sauce has thickened.
Now add the seafood mix to the sauce and cook for an additional 5-minutes.
Pour the mixture into the prepared ramekins, then top with shredded cheddar cheese.
Bake for 15 minutes to heat through and melt the cheese on top.